Palaentology of Mesozoic terrestrial deposits on Axel Heiberg Island, Arctic Canada (Nunavut Palaeontology Permit 04-02P) N. Rybczynski

Background: The Arctic through the Mesozoic (=Age of the Dinosaurs) Over the past 250 million years, the Arctic landmass has undergone enormous environmental change. At the beginning of the Age of Dinosaurs, it was part of the “supercontinent”, Pangea, and was located at about 40° N. As Pangea split apart North America drifted northward. It was not until the end of the age of dinosaurs, about 70 million years ago, that the Arctic landmass came to rest at approximately the latitude it is found at today.

The climate of the arctic landmass has changed with its latitudinal position, and also with patterns of global climate change. Because the Arctic land mass has experienced enormous environmental change through the Mesozoic it presents excellent opportunities for understanding how terrestrial plants and animals respond to these enormous environmental changes.

The expedition In July 2004 five researchers went to Axel Heiberg Island in search of fossil evidence that could be used to understand the effects of climate change through the Age of Dinosaurs. The team was led by Natalia Rybczynski (Canadian Museum of Nature), and Hans Larsson (McGill University). The team prospected the South and Southwest parts of the Island over 24 days, and collected fossils from five rock formations. Fossils include petrified wood, fossil leaves and cones, fossil freshwater molluscs (ex. Mussels and snails) and marine mollusks (ex. Ammonites). Skull remains of a marine reptile were also recovered.

The Ancient History of Axel Heiberg Island. The earliest fossils recovered are of Triassic-Jurassic in age (roughly 200 million years old). They show that Axel Heiberg Island was once covered by a richly diverse plant community that included forests. During the Mesozoic the island was at times partially inundated by the seawater, and the presence of petrified wood in some marine sediments indicates that the shoreline was usually not too far from the forest. The presence of petrified wood also indicates that the area was forested probably throughout the Mesozoic.

The collections Most of the collections are currently being held for Nunavut at the Canadian Museum of Nature (Ottawa). However, part of the collection is being studied at McGill University (Montreal).

Photo 1: Prospecting for fossils

Photo 2: Late Cretaceous Inoceramid, Strand Fiord

Photo 3: Triassic age fossil plant